Magnetism and superconductivity: a quantum duel at the edge of absolute cold

Albin De Muer (IUT1 - MP)
Scientific and technical culture
The research presented by Albin De Muer focuses on rare earths, materials that have very interesting electronic properties for industrial applications as well as for physics.
Within these materials, such as cerium, two types of antagonistic interactions arise due to the atom's peripheral electrons. The same interaction between electrons initially leads to the suppression of magnetic moment (Kondo interaction) and, at the same time, to the emergence of long-range magnetic order (RKKY interaction). As the temperature drops, the interactions between the magnetic moments of the electrons create an antiferromagnetic order. The temperature below which antiferromagnetic order appears drops to absolute zero (-273.15°C, the temperature at which nothing moves). Near this quantum critical point, a bubble of superconductivity appears (emergence of exotic physics), which remains unexplained to this day.

In this state of superconductivity, resistivity (electrical resistance) drops sharply to 0, allowing current to flow without energy loss. The theoretical understanding is well known for pure metals, but not for rare earths, for which the occurrence of this phenomenon cannot yet be explained. Abin's research focuses on this phenomenon, and he conducts experiments on large equipment at the National Laboratory for High Magnetic Fields (LNCMI) to reach the quantum critical point.

 
Updated on January 14, 2026